Preheat the oven to 300 F. Cut the tomatoes in half and toss them in a bowl with half the oil and some salt and pepper. Arrange skin-side down on an oven tray and bake for an hour, until the tomatoes have lost much of their moisture. About 20 minutes before the tomatoes are ready, start on the hotcakes. Combine the cheeses, milk and egg yolks in a large bowl, stir in the flour and a quarter tsp of salt, and mix to a uniform batter. Pour the egg whites into a separate bowl and whisk until foamy but not totally stiff. Fold into the ricotta mix. Heat half the butter in a large, nonstick frying pan. Drop in two to three TB of batter per pancake and use the back of the spoon to help shape them into round pancakes roughly 1 cm thick and 10 cm in diameter. Cook for a minute or two on each side, until golden. Keep warm and repeat with the remaining batter. Mix the remaining oil, garlic, vinegar and some salt and pepper in a bowl. Add the spinach and using your hands, toss gently. Serve two pancakes per person, topped with the spinach salad and tomatoes and finished off with a sprinkling of fresh basil and pine nuts. Serve at once.